The reduction of alumina and aluminum hydroxide and their hydrates (oxidic aluminum) with carbon (carbothermic reduction) was known long before the currently used electrolytic reduction method was introduced. Initially, the carbothermic reduction of bauxite or pure aluminum oxide produced little or no metallic aluminum. The presence of aluminum carbide was shown and when the carbothermic reduction of bauxite was effected at 2000.degree. C and 1 atmosphere (atm) air pressure, large losses were caused by vaporization. In order to overcome this problem Cowles added iron, copper or nickel to the bauxite/carbon mixture to prevent the formation of aluminum carbide (American Journal of Science 3, (1885), 308). At 2000.degree. C and 1 atm air pressure, aluminum alloys were obtained. Later, it was shown that aluminum could be successfully distilled in vacuo from the aluminum alloys at 1500.degree. C (French Pat. No. 474,375).
The process of this invention improves the yield of aluminum at lower temperatures.